This invention relates to a solid state electrochemical sensor for selectively sensing chemical species in a fluid.
Solid state electrochemical sensors for detecting, measuring and monitoring chemical species and properties (e.g. ion activity and concentration, concentration of enzymes, substrates, antibodies, antigens, etc.) generally fall into two categories--potentiometric sensors which utilize some type of chemical layer which is sensitive to ions or some neutral molecules (see, for example, U.S. Pat. No. 4,020,830), and amperometric sensors in which a mass transport limited current provides infomation about the concentration of reducible or oxidizable species (see, for example, U.S. Pat. No. 2,913,386). The latter type of sensors typically suffer from lack of selectivity, that is, from an inability to detect the presence of a particular chemical species in a fluid in which other chemical species may also be present. However, in spite of these and other difficulties with presently known solid state electrochemical sensors, there is still a great deal of interest in finding a practical, solid state, miniaturized sensor which can selectively detect the presence of various chemical species.